It's amazing how much of an impact a seemingly basic maintenance procedure can have on the big picture—not only from the standpoint of performance but also of the safe operation of your vehicle. In Part 1 of The Dirty Dozen, we looked at six basic yet important talking points, including cleanliness, clearance, tires, brakes, coolant, and engine oil level. We'll now address the second sinful six-pack of oversights, misunderstandings, and misinformation that are sometimes lost on the DIY enthusiast.
1. Don't Blow Out Your Seals
Get the Fluid Levels Right in Your Driveline
Benefit: Ensure optimal lubrication for the transmission, transfer case, and differential
In Part 1, we talked about how too much—or too little—oil could cost you an engine. Similarly, your driveline requires lubricants in the transmission, transfer case (for all-wheel drive), and differential carrier (for all-wheel drive and rear-wheel drive). And, like your engine, it requires just the right amount of fluid for optimal performance. Since all moving parts in your driveline are semi-submersed in lubricants, underfilling will obviously provide inadequate lubrication, resulting in accelerated wear and, eventually, failure. You can also expect these moving parts to aerate the fluid. In anticipation of this, manufacturers typically incorporate a vent or port to release the pressure that builds up during aeration to ensure it does not cause the seals to leak. If you overfill, the excess fluid will become aerated and will most likely leak fluid from the overflow vents or even cause seals to fail.
2. Help Your Hydraulics
Flush and Bleed Your Hydraulic Systems for Optimal Performance
Cost: Less than $20 for most brake fluids; up to $60-plus for racing fluids
Benefit: Replace your hydraulic fluids to purge moisture, impurities, and air from the lines
Another commonly skipped step is the flushing, filling, and bleeding of hydraulic systems. Typical hydraulic systems in passenger cars include the brakes, power steering, and, in the case of a hydraulic manual transmission, the clutch. These systems employ fluid to actuate a given accessory. For example, when you step on the brake pedal, fluid displaces the piston(s) in the brake caliper, squeezing the brake pads against the rotor to generate friction to stop your vehicle. A common mistake is to simply swap out the worn pads and/or rotors without flushing, refilling, and bleeding the brake fluid. Just because you can't see the fluid (or since the fluid is within a closed circuit/system), doesn't mean you can forget about it. First of all, brake fluid is hygroscopic (attracts water molecules). When this happens, you end up with water in the hydraulics that can cause corrosion. Bleeding the system is important to ensure all air bubbles have been purged from the system. Why is this important? Because air compresses while fluid does not. Thus, even the smallest pockets of air in the system will negate the effects of the brake hydraulics, which could in turn result in a spongy or unresponsive brake system. Usually, fluid should be flushed, refilled, then bled whenever the brake pads/rotors are serviced, or once a year—whichever comes first. This simple service is imperative for safety and reliability. It's a good idea to flush, refill, and bleed the clutch and power steering fluids according to the manufacturer's recommended schedule. It's also good practice to perform this maintenance whenever the clutch is being serviced.
3. Too Much of a Good Thing
Benefit: Your car stays together as the manufacturer intended
Tight makes right...or does it not? When it comes to tightening and securing fasteners, just right is enough. The application of torque to fasteners, which is the act of tightening nuts or bolts to a specified level, is a more precise science than merely tightening until a nut or bolt stops turning or "feels tight." If the fastener is too loose, it could back out and become loose or allow components to come undone. On the other hand, is it possible to have too much of a good thing by overtightening fasteners? Absolutely! From bolting on a new wing to torquing your new head studs, overtightening can lead to sheared fasteners or worse: stripped threads and damaged engine components. Repairing stripped threads is a tedious and undesirable process. To avoid creating unnecessary work for yourself, be sure to double-check the torque specifications as recommended by the vehicle or component manufacturer to ensure parts stay where they belong without breaking fasteners.
4. Keep Your Wheels Secured and Turning
Torquing Lug Nuts
Benefit: Your wheels stay where they belong: secured to the hubs
Fasteners that see a lot of action are lug nuts. They keep your wheels secured to the hubs, thus torquing them properly is a must. Fortunately, the factory wheel studs are quite strong and capable of sustaining significant levels of torque. However, it is important to apply the proper levels of torque for the type of lug nuts you are using, which could be chromoly, titanium, or aluminum. Chromoly is the standard material for lug nuts on just about everything with wheels. These can usually be torqued beyond the factory recommended level if necessary. This is of particular benefit when going to the track, where you end up retorquing the lug nuts after each run session. Titanium lugs are lighter than chromoly, stronger than aluminum, and can be torqued to the same levels as chromoly. The lightest lug nuts are made from aluminum, and some are forged for added strength. Just remember: Forged aluminum is still a softer metal than the steel wheel studs it's being threaded onto. Be sure to double-check the torque values for the aluminum nuts as recommended by the manufacturer (as they may not match the vehicle manufacturer's recommendations) to keep from stripping out the threads.
5. Stay Pointed in the Right Direction
Wheel and Tire Alignment
Cost: $50 to 150
Benefit: A proper alignment will optimize chassis dynamics and improve handling
Contrary to (seemingly) popular belief, alignments are not permanent, and automobiles are not self-aligning. Yet it's common to see misaligned vehicles on the road. Some alignment issues are not immediately apparent. However, inspection of the tire tread could reveal alignment issues. In other instances, vehicles are blatantly misaligned, with alignments that are so far off it's unimaginable that anyone could drive the vehicle without noticing the car pulling to one side or having to constantly make steering corrections because the steering wheel provides a feeling of uneasiness. An alignment ensures your vehicle will track straight with the steering wheel straight. A proper alignment will also mitigate irregular tire wear for improved efficiency, cost savings, and tire longevity. A proper alignment does more than ensure proper tire wear. It lends to improved handling and helps build a driver's confidence around turns on winding roads or on a road course at the track. It also ensures the car behaves predictably, or, at the very least, as you'd expect it to.
6. Beware of Bad Bushings
Inspect Suspension Bushings
Benefit: Optimal ride quality and handling, no sketchy moments on the street or track
Suspension bushings are often overlooked since most people don't think they will wear out. However, for enthusiasts who enjoy the driving experience and keep their ride for years, it's worth taking a periodic look at the suspension bushings to be sure they aren't torn or completely broken. Bushings help absorb irregularities in the road while returning the suspension arms to the proper position when the pavement smooths out. However, bushings also serve as a pivot point, permitting the suspension to travel with a certain range of movement. If a bushing is torn, it no longer keeps the suspension arm or link in its proper plane of motion, resulting in changes to the geometry that will affect handling and ride quality. Broken or damaged bushings are often the source of a lot of squeaks and rattles and could also pose a risk to the safe operation of the vehicle since the handling could become compromised or unpredictable. If they're broken, get 'em fixed.